STUDIES    IN 
SMALL-POX    AND    VACCINATION 


STUDIES   IN 
SMALL-POX  AND  VACCINATION 


WILLIAM     HANNA,     M.A.,     M.D.,     D.P.H. 

Assistant  Medical  Officer  of  Health  for  the   Port   of  Liverpool ; 
Visiting  Physician  to  the   Port  Isolation   Hospital. 


NEW     YORK: 
WILLIAM     WOOD     AND     COMPANY. 

MDCCCCXIII. 


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PREFACE 

The  following  studies  on  the  subject  of  small-pox  and  its 
prophylaxis  by  vaccination  have  been  the  outcome  of 
several  years  of  observation  of  cases  which  have  occurred 
in  the  City  and  Port  of  Liverpool.  Ample  opportunity 
has  been  afforded  for  this  study  from- the  unique  position 
of  Liverpool  as  a  shipping  centre,  and  tlie  great  tide  of 
alien  traffic  which  flows  through  it. 

The  first  and  second  parts  deal  with  the  ever-important 
problem  of  the  value  of  vaccination  in  preventing  and 
mitigating  attacks  of  this  dreaded  malady,  and  the  inverse 
relationship  of  scar-area  to  severity  of  attack  is  pointed  out. 

The  final  portion  treats  of  "  Concurrent  Small-pox 
and  Vaccination "  :  a  very  interesting  and  important 
subject. 

It  is  hoped  that  the  book  will  appeal  to  Medical 
Officers  of  Health,  Vaccination  Officers,  and  those  in  cliarge 
of  Infectious  Disease  Hospitals.  In  addition,  general 
practitioners  may  find  it  useful  in  furnishing  illustrations 
of  cases  of  smaU-pox.  The  work  also  contains  useful 
and  striking  diagrams  and  arguments  as  to  the  value  of 
vaccination  and  re-vaccination  which  may  be  used 
with  parents  and  others  who  object  to  these  preventive 
operations. 

I  am  indebted  to  Dr.  E.  W.  Hope,  Medical  Officer  of 
Health,  City  and  Port  of  Liverpool,  for  much  valuable 
criticism,  and  to  Dr.  N.  E.  Roberts,  Visiting  Physician, 
Liverpool  City  Hospitals,  for  the  loan  of  some  photo- 
graphs which  have  enabled  me  to  complete  my  series 
illustrating  the  various  points  in  the  text. 

Liverpool,  W.    HANNA. 

February,  1913. 


281496 


CONTENTS 


PAGES 

Introduction     .......     7-10 


Part  I. — A  Statistical  Study  of  1,163  Cases  of  Small-pox, 
WITH  Special  Reference  to  Vaccination  in  Modifying 
THE  Disease  ......   11-26 


Part  II. — An  Analysis  of  943  Cases  of  Small-pox  (with 
Primary  Vaccination)  in  Relation  to  Scar-area  and 
Severity  of  Disease  ....  27-34 


Part  III. — Observations  on  the  Interaction  of  Concurrent 

Variola  and  Vaccinia        .....  35-49 


Conclusions       .  .  .  .  ...       51 


STUDIES    IN 
SMALL-POX    AND    VACCINATION 


INTRODUCTION. 


A  STUDY  of  the  early  history  of  small-pox,  before  vac- 
cination was  introduced,  shows  that  the  disease  was  one  of 
extensive  prevalence  and  great  malignancy.  In  the  i8th 
century  it  reached  its  highest  point  of  intensity  and  dis- 
tribution in  Europe,  the  mortality  from  smaU-pox  in 
England  at  that  period  being  one-tenth  of  the  total 
mortality.  In  London  it  was  constantly  present,  and  the 
deaths  averaged,  during  the  period  1761-1796,  from 
3,000  to  15,000  yearly  ;  indeed,  in  the  latter  half  of  the 
century  the  deaths  seldom  fell  below  1,000.  The  great 
mahgnancy  of  the  disease  when  introduced  into  fresh 
countries  in  later  years  has  also  been  frequently  recorded. 
The  decrease  in  smaU-pox  prevalence  since  the  beginning 
Lol  the  19th  century,  and  the  marked  reduction  in  its 
I  fatality,  have  been  shown  to  be  due  to  the  protection 
afforded  by  the  process  of  vaccination. 

There  is  no  subject  of  medical  or  scientific  interest 
which  has  given  rise  to  such  controversy  as  that  of  the 
value  of  vaccination.  In  the  early  days  of  its  introduction, 
Jenner  did  not  stand  alone,  for  Woodville  and  Pearson, 
physicians  to  the  SmaU-pox  Hospital  in  London,  made 
numerous  experiments  and  came  to  the  same  conclusion 


as  Jenner,  that  the  process  conferred  protection  against 
small-pox.  The  systematic  observations  of  many  quali- 
fied observers  have,  however,  long  since  turned  the  tide 
in  favour  of  the  upholders  of  the  practice  as  a  scientific 
and  prophylactic  measure,  and  it  is  unnecessary  now  to 
draw  attention  to  the  convincing  figures  which  have 
proved  its  value.  It  is  sufficient  to  state  that  from  a 
long  study  of  the  pock  diseases  of  animals,  especially  vac- 
cinia or  cow-pox,  and  from  experiments  and  observations 
made  by  scientists,  the  relationship  of  variola  and  vaccinia 
has  now  been  established  on  a  firm  basis  of  fact.  The 
experiments  of  such  observers  as  Thiele,  Ceely,  King  and 
Hime,  and  more  recently  of  Klein  and  Copeman,  have 
shown  that  it  is  possible  to  inoculate  a  calf  with  small-pox 
material  and  to  obtain  a  vesicle  at  or  near  the  site  of 
inoculation,  identical,  or  almost  so  in  the  first  instance, 
with  a  human  vaccine  vesicle.  This  vesicle  becomes  even 
more  typical  in  the  case  of  successive  inoculations,  and  the 
result  is  practically  the  same  as  if  the  animal  had  been 
inoculated  with  vaccinia,  for  the  calf  is  no  longer  susceptible 
to  vaccination.  In  addition,  the  lymph  from  these  vesicles 
has  been  transferred  and  used  to  inoculate  successfully 
human  individuals,  and  the  attenuated  virus  confers 
protection  against  human  small-pox  as  ordinary  vac- 
cination does. 

(  Small-pox  still  continues  to  invade  our  shores  from 
abroad,  the  extensive  movements  of  populations,  the 
rapid  means  of  communication,  and  the  travelling 
facilities  afforded  by  fast  steamships,  enabling  the  disease 
to  jeopardize  our  ports  and  the  country  generally,  even 
more  so  than  heretofore.  Countries  such  as  Canada,  the 
United  States  of  America,  Spain,  Russia,  Egypt,  etc.,  are 
well  within  the  incubation  period  of  the  disease,  and  from 


time  to  time  persons  have  been  landed  in  our  ports  in  the 
incubation  stage. 

In  the  interval  after  a  great  epidemic,  material  will 
gradually  accumulate  in  the  shape  of  large  numbers  of 
susceptible  children  in  districts  where  primary  vaccination 
has  not  been  carried  out  with  strictness,  e.g.,  in  the  London 
Metropolitan  Unions,  where  the  number  of  children  not 
finally  accounted  for  (including  cases  postponed  and  for 
which  "certificates  of  exemption"  were  granted)  per  cent 
of  total  births  in  the  respective  years  was  as  follows  :  — 

1893-97  -  -  -  23-9  % 

1899-1906  -  -  -  23-5  % 

1907  -  -  -  -  25-8  % 

1908  -  -  -  -  28-8  % 

1909  -  -  -  -  307  % 

It  will  thus  be  seen  that,  just  before  an  epidemic,  a 
large  proportion  of  children  in  some  large  towns  may  be 
unprotected  by  vaccination.  In  Liverpool  the  percentage 
not  finally  accounted  for  is  comparatively  small,  being 
about  5  per  cent.  Again,  those  who  have  escaped  the 
epidemic  owing  to  good  vaccination  lose  some  of  this 
immunity  as  years  pass,  or  in  the  words  of  the  late  Dr. 
Bond,  of  Gloucester,  "  become  de- vaccinated  "  and  so 
provide  suitable  material  for  the  next  outbreak,  when  the 
virulence  of  the  disease  may  succeed  in  breaking  down  a 
comparative  insusceptibility. 

The  liability  of  a  population  to  a  small-pox  epidemic 
therefore  ma}'  be  measured  by  its  density  at  susceptible 
ages. 

After  a  long  spell  (seven  years)  of  comparative  quies- 
cence, the  disease  broke  out  in  epidemic  form  in  Britain 
in  1902-3  ;    it  carried  off  a  large  number  of  persons  ;    in 


10 

the  City  of  Li\'erpool  alone  there  were  during  that  period 
2,280  cases,  with  161  deaths. 

This  epidemic  of  small-pox  was  extensively  prevalent 
in  Europe  and  America,  and  tlie  first  Liverpool  cases 
were  introduced  amongst  cattle-men  from  Boston,  U.S.A. 
The  disease  was  raging  in  Boston,  and  many  cattle-men, 
employed  on  cattle  boats  from  the  United  States,  landed 
in  Liverpool ;  these  men  were  frequently  incubating 
small-pox,  and  subsequently  developed  symptoms  of  the 
disease  in  the  various  lodging-houses  of  the  citj^  These 
foci  helped  on  the  gradual  evolution  of  the  epidemic  which 
was  extending  over  the  country.  London  and  other  large 
centres  became  infected  about  the  same  time.  In  London 
the  disease  originated  in  a  Pole,  residing  in  Stepney,  who 
had  returned  from  a  visit  to  Paris  ;  subsequent  importa- 
tions came  from  Egypt  and  elsewhere. 

The  series  of  small-pox  cases  under  consideration  has 
been  collected  from  amongst  those  which  have  been 
admitted  to  the  hospitals  of  the  City  and  Port  of  Liverpool 
during  the  past  ten  years.  The  large  majority  occurred 
during  the  above-mentioned  epidemic  period  (1902-3),  and 
since  then  the  cases  admitted  have  been  chiefly  imported 
from  abroad. 

All  the  cases  which  occurred  during  the  epidemic 
were  not  available  for  the  purposes  of  this  investigation, 
owing  to  the  fact  that  the  method  of  recording  the  required 
particulars  was  not  at  first  adopted. 


11 


PART   I. 

A  STATISTICAL  STUDY  OF  1,163  CASES  OF  SMALL-POX, 

WITH    SPECIAL    REFERENCE   TO   VACCINATION 

IN    MODIFYING   THE    DISEASE. 

The  examination  of  a  large  series  of  cases  of  small-pox  is 
of  value  as  affording  additional  testimony  to  the  effiicacy 
of  vaccination  as  a  prophylactic  measure,  as  an  estimate 
of  the  severity  of  the  disease,  and  of  the  mortality  gener- 
ally in  the  vaccinated  and  unvaccinated ;  and  in  particular, 
the  measure  of  the  efficiency  of  the  vaccination  in  the  case 
of  the  vaccinated.  Some  new  methods  have  been  adopted 
in  recording  and  comparing  this  series  of  cases. 

It  has  been  noted  from  time  to  time  in  vaccination 
records,  e.g.,  those  of  Russell,  Marson,  Gayton,  and  others, 
that  the  quality  and  size  of  the  scar-area  have  an  important 
bearing  on  the  amount  and  extent  of  the  eruption,  and 
consequently  on  the  severity  of  the  disease.  Attention, 
however,  was  only  directed  to  counting  the  number  of 
vaccination  scars,  estimating  their  qualit}',  or  approximat- 
ing their  area,  and  verj'  little  has  been  done  to  measure 
accurately  this  scar-area  and  to  consider  its  relation 
to  severity  and  mortality  at  different  age  periods. 

The  cases  of  small-pox  numbered  1,163,  consisting  of 
943  vaccinated  in  infancy  and  220  unvaccinated. 

The  method  adopted  was  that  of  tabulating  the  age, 
the  presence  or  absence  of  vaccination  scars,  and  in  the 
former  case  of  measuring  the  area  in  square  inches. 


12 

The  cases  were  placed  in  ten  age-groups,  and  arranged 
in  order  to  show  the  proportion  of  vaccinated  and  un- 
vaccinated  in  each.  These  have  been  set  out  in  Tables  I 
and  //,  where  the  extent  and  severity  of  the  disease  are 
also  revealed.  The  influence  of  vaccination  on  the  mor- 
tality will  be  first  considered. 

Influence  of  Vaccination  on  the  Case-mortality. 

Whilst  there  are  several  criteria  of  the  severity  of  the 
disease,  such  as  extent  of  eruption,  temperature,  etc.,  the 
one  of  most  value  is  the  case-mortality.  When,  therefore, 
a  comparison  is  made  of  the  influence  of  vaccination 
on  the  case-mortality  of  small-pox,  it  will  be  seen  that 
amongst  the  943  cases  which  were  vaccinated  in  infancy, 
there  were  twenty-eight  deaths,  or  2-9  per  cent,  and 
amongst  the  220  unvaccinated  cases  there  were  sixty 
deaths,  or  272  per  cent;  'that  is,  the  ratio  of  deaths  to 
attacks  is  ten  times  as  great  in  the  unvaccinated  as  in 
the  vaccinated  {see  Table  II,  page  14). 

These  percentages  are  almost  identical  with  Marson's 
well-known  figures,  viz.,  about  8  per  cent  in  those  alleged 
to  be  vaccinated  with  or  without  evidence,  and  35-5  per 
cent  for  the  unvaccinated  ;  these  figures  are  the  result  of 
twenty-five  years'  (1835-60)  observations  on  post-vaccinal 
small-pox  at  the  London  Small-pox  Hospital.  Dr.  Russell's 
figures  for  Glasgow  (1871-72)  were  3  per  cent  for  the 
vaccinated  and  30  per  cent  for  the  unvaccinated. 

Dr.  Woodward,  dealing  with  the  last  twenty-five  years 
of  the  i8th  century,  when  all  the  patients  were  un- 
vaccinated, states  that  the  death-rate  was  32  per  cent  of 
the  admissions  to  the  Small-pox  Hospital.  Dr.  Gayton's 
figures  for  the  metropolitan  hospitals  showed,  in  the  well 


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and  imperfectly  vaccinated,  a  case-mortality  of  from  3  to  g 
per  cent,  whilst  it  reached  over  40  per  cent  in  the  un- 
vaccinated,  and  in  various  other  places  it  was  just  as  high. 

The  small-pox  of  the  last  decennium  has  been  of  a 
fairly  mild  type.  The  question  of  age  distribution  in  the 
population  attacked,  and  the  country  of  origin  of  the 
disease,  may  have  an  important  influence  in  determining 
the  virulence  of  an  epidemic. 

On  the  Chart  A  (pages  16,  17)  and  in  the  accompany- 
ing tables,  the  cases  have  been  arranged  into  suitable  age 
periods,  so  as  to  show  clearly  the  value  of  vaccination  on 
the  mortality  in  passing  from  infancy  to  adult  and  old  age. 
An  examination  of  the  deaths  recorded  amongst  the 
vaccinated  under  each  age-group  reveals  the  interesting 
fact  that  no  death  occurred  until  the  20-30  year  group  is 
reached,  and  the  case-mortality  for  this  group  is  only 
0"9  per  cent.  It  will  be  observed,  however,  that  the 
percentage  case-mortality  amongst  the  vaccinated  steadily 
rises  from  this  point  onwards  in  life,  but  never  exceeds 
10  per  cent. 

On  contrasting  these  figures  with  those  amongst  the 
unvaccinated,  we  observe  a  striking  difference.  Under 
2  years  of  age  the  deaths  are  58  per  cent  of  the  cases 
attacked,  for  2-5  years  30'6  per  cent,  and  the  figure  then 
falls  until  10-15  years,  when  it  is  3-2  per  cent. 

This  decrease  may  be  attributed  to  the  gradual 
development  of  the  natural  resistance  and  recuperative 
power  of  youth  enabling  the  patient  to  recover  from  the 
disease ;  this  may  be  compared  with  what  is  observed  in 
other  infectious  diseases.  From  adolescence  onwards  the 
mortality  in  the  unvaccinated  gradually  increases,  until  it 
reaches  50  per  cent  at  the  periods  from  40  years  and 
upwards.     This  high  ratio  of  deaths  to  attacks  amongst 


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the  unvaccinated,  especially  at  the  early  and  late  periods 
of  life,  compares  with  what  is  well  known  of  this  disease  in 
pre- vaccination  days,  viz.,  that  the  severity  and  mortality 
lay  heaviest  on  infants  and  young  children  under  ten  years 
of  age.  The  large  excess  of  births  and  rapid  accumulation 
of  susceptible  persons  in  the  growing  manufacturing  towns 
afforded  ample  material  for  an  epidemic  to  feed  upon; 
therefore  the  number  of  adults  and  old  people  who  had 
escaped  the  disease  in  pre-vaccination  days  was  few. 
At  the  present  time,  when  an  epidemic  spreads  over  the 
country,  in  addition  to  the  unvaccinated  children,  the 
disease  also  attacks  those  adults  who  have  never  been 
vaccinated  in  their  youth,  and  in  addition,  the  power  of 
recovering  from  small-pox  decreases  as  age  advances. 


The  Influence  of  Vaccination  on  the  Eruption,  and 
ON  the  Severity  of  the  Disease. 

The  amount  of  eruption  on  the  body  of  a  patient 
affected  with  small-pox  always  gives  one  an  opportunity 
to  form  an  opinion  of  the  severity  and  probable  -  fatality 
of  the  case. 

The  eruption  may  be  divided  into  five  categories,  and 
commencing  with  the  very  mildest,  these  are  as  follows  : 
modified  discrete,  discrete,  profuse  discrete,  semi-confluent, 
and  confluent.  For  purposes  of  easy  examination  they 
have  been  grouped  with  the  descriptive  terms  as 
follows  : — 

A. — Modified  discrete  and  discrete,  representing  the 
mild  types  of  the  disease. 

B. — Profuse  discrete  and  semi-confluent ;  a  moderate 
type  of  severity. 


PLATE     I 


A  IMILD    AND     MODIFIED    CASE    OF     SMALL-POX 


Patient  well  vaccinated  in  infancy,  the  scar  area  approximating  one  square  inch. 
Age  twentv-five  years.  Note  the  mild  character  of  the  eruption,  which  is,  as  usual, 
chiefly  confined  as  regards  distribution  to  the  face  and  extremities.  The  usual 
freedom  of  the  triangle  of  the  neck  from  eruption  is  to  be  noted. 


PLATE      J 11 


WELL-MARKED    CASE    OF     SMALL-POX    OF     SEVERE    CHARACTER    IN    A    MAN     WHO 
NEVER    BEEN    VACCINATED    UNTIL    AFTER    INFECTION    WITH    SMALL-POX 


Patient  unvaccinated  in  infancy.  Vaccinated  for  first  time  seven  days  before 
onset.  Age  twenty-two  years.  Note  the  severity  of  tlie  case,  tlie  size  of  the 
pustules,  and  distribution  of  the  eruption,  more  marked  on  face  and  extremities 
than  on  body.  The  vaccination  has  been  successful,  and  without  doubt  saved  the 
man's  life;    he  recovered  completely.     Photo  taken  on  ninth  day  of  eruption. 


19 

C. — Confluejtt  or  very  severe  ;  to  this  last  category 
have  been  added  those  in  which  death  occurred. 

There  are  therefore  three  types  of  severity,  viz., 
A  mild,  B  moderate,  and  C  severe  {see  Plates  I,  II, 
and  III). 

Let  us  examine  the  eruption  and  severity  at  different 
ages,  as  it  occurs  in  the  natural  disease,  i.e.,  in  the 
imvaccinated  {see  Chart  A,  page  i6). 

An  examination  of  the  column  under  0-2  years  of  age 
shows  that  over  58  per  cent  of  the  cases  at  this  age  period 
are  found  with  the  fatal  kind  of  small-pox,  31  per  cent  with 
the  medium  type,  and  only  10  per  cent  with  the  mild  form 
of  the  disease ;  the  same  is  also  the  case  for  the  period  2-5 
years,  showing  the  marked  incidence  of  the  severe  kind  on 
unvaccinated  childhood. 

Contrast  in  Chart  A  the  severity  of  the  disease  and 
mortality  under  10  years  of  age  in  the  unvaccinated  with 
the  similar  columns  in  the  vaccinated. 

The  middle  period  of  life  has  a  lower  percentage  of 
severe  cases  ;  this  may  be  explained  by  the  higher  resistance 
of  the  body  and  power  of  recovery,  which  gradually  increase 
up  to  30-35  years  of  age  ;  this  natural  resistance  is  well 
shown  in  the  unvaccinated  in  Chart  A. 

The  number  of  cases  of  moderate  severity  continues 
high  in  the  unvaccinated  throughout  life,  but  as-  age 
advances,  the  very  severe  type  again  appears. 

The  dark-shaded  portion  in  the  chart  indicates  the 
mortality  limit  amongst  the  severe  cases  ;  and  it  will  be 
observed  that  from  10  years  onwards  to  40  years  many 
severe  and  confluent  cases  recover.  Compare  this  with 
the  severe  cases  followed  by  death  in  children  under 
10  years  and  in  old  people,  that  is,  at  the  extremes  of 
life. 


20 

I.  Influence  on  the  Extent  of  the  Eruption. 

The  effect  of  vaccination  is  to  reinforce  the  natural 
immunity  of  the  body.  When  it  does  not  prevent  the 
onset  of  the  disease,  it  may  either  influence  the  extent  of 
the  eruption  or  modify  the  character  of  the  individual 
papules.  Let  us  consider  first  the  influence  of  vaccination 
on  the  extent  of  the  eruption.  On  contrasting  in  Tables  I 
and  //  and  Chart  A,  the  primarily  vaccinated  cases  under 
the  different  age-groups,  a  distinct  series  of  facts  will 
become  apparent.  In  the  first  place,  there  are  no  cases 
recorded  under  2  years*,  and  only  seven  cases  under 
5  years ;  the  latter,  moreover,  were  exceedingly  mild  in 
character  and  characterized  by  very  sparse  eruptions,  a 
few  papules  only  appearing  in  isolated  parts  of  the  body. 
Again,  only  three  cases  of  moderate  severity  appear  under 
10  years  of  age,  and  of  the  severe  type  no  cases  are 
recorded  under  20  years.  When  the  columns  of  vaccin- 
ated persons  in  Table  II  are  contrasted,  it  will  be  seen 
that  the  percentages  of  persons  with  the  different  forms 
of  the  disease  are  graduated  :  the  highest  percentages  in 
each  age  group  are  found  to  have  the  disease  in  a  mild 
form,  the  next  highest  in  moderate  form,  and  so  on;  the 
most  severe  cases  show  the  lowest  percentage  and  only 
appear  after  25-30  years  of  age,  and  the  deaths  occurring 
in  this  period  are  comparatively  low. 

On  the  total  cases  of  all  ages  amongst  the  vaccinated, 
the  percentages  are  727  of  mild  type,  237  moderate,  and 
only  3 '6  of  a  severe  character. 

The  protection  afforded  by  vaccination  against  attacks 
of  the  disease  is  therefore  well  seen  in  this  investigation, 
where  no  cases  of  small-pox  in  the  vaccinated  are  to  be 
found  under  2  years  of  age*  {see  pages  13,  14,  16),  that  is, 

*  See  footnote,  page  31. 


21 

in  the  years  immediately  following  upon  the  process   of 
vaccination. 

II.  Influence  in  Modifying  the  Character  of  the 
Specific  Eruption. 

The  eruption  of  unmodified  small-pox  usually  passes 
through  a  well-recognized  series  of  changes. 

The  first  appearance  of  the  eruption  takes  place 
approximately  three  days  after  the  onset  of  symptoms,  as 
red  spots  about  the  size  of  a  pin's  head,  first  seen  chiefly 
on  the  forehead  and  wrists.  They  cannot  be  felt  as  distinct 
spots  above  the  skin,  and  disappear  on  pressure.  Shortly 
after,  they  swell  into  raised  pink  papules,  fairly  hard  and 
easily  perceptible  to  the  touch ;  they  grow  in  size  and  can 
frequently  be  recognized  as  "  shotty,"  but  this  depends  on 
their  position  in  the  skin  and  the  tension  of  the  contents 
due  to  effused  fluid.  After  a  day  or  so,  when  they  have 
become,  in  typical  cases,  rounded  and  defined,  vesiculation 
develops,  and  at  the  beginning  of  the  third  day  the  papules 
have  become  vesicular.  These  vesicles  are  loculated,  and  if 
pricked,  the  clear  contents  will  escape  in  small  amount. 
The  loculation  is  due  to  trabeculae  running  through  the 
interior  which  divide  the  pock  into  several  compartments. 
These  vesicles  gradually  become  opaque  or  grey  in  colour, 
and  the  contents  become  pustular  ;  this  happens  about  the 
sixth  day  of  the  eruption,  and  by  the  eighth,  ninth,  or 
tenth  day  they  begin  to  dry  up,  with  the  formation  of 
crusts.  This  is  the  typical  course  in  all  cases  except 
those  of  a  severe  or  hsemorrhagic  character.  In  cases 
modified  by  vaccination,  various  interesting  changes  may 
be  demonstrated  in  the  character  of  the  eruption. 

The  following  modifications  in  the  eruption  due  to 

3 


22 

vaccination  have  been  noted  in  the  series  under  examina- 
tion. 

1.  The  papules  have  been  numerically  few  in  number 
and  limited  to  isolated  parts  of  the  body.  They  have, 
however,  gone  through  the  typical  course  of  evolution. 

2.  The  rash  has  been  profuse,  but  the  lesions  were 
superficially  placed ;  the  vesicles  or  pustules  were  frequently 
small  or  irregular  in  size,  and  owing  to  their  superficial 
position  were  unilocular,  like  vesicles  in  chicken-pox  ;  in 
some  cases  they  evolved  quickly,  and  suppurated  early  and 
imperfectly. 

3.  The  papules,  owing  to  wart-like  masses  of  granula- 
tion tissue  formed  at  the  base,  appeared  as  raised  fleshy 
elevations. 

4.  A  concurrent  vaccination  might  cause  rapid 
inspissation  of  the  pustules,  the  crusts  dropping  off  early. 

In' the  accompanying  Plate  IV,  the  first  type  is  well 
illustrated  ;  the  rash  is  very  sparse,  the  papules  passing 
through  the  various  typical  stages  as  in  natural  small- 
pox, attaining  full  size.  The  type  described  under 
No.  2  is  well  shown  in  Plate  V,  where  the  rash  is  very 
profuse,  but  the  individual  lesions  are  much  smaller  than 
those  occurring  in  natural  small-pox,  the  pustules  varying 
in  size  from  a  pin's  head  to  a  pea  within  a  small  area  ;  they 
are  superficially  placed  in  the  skin,  and  the  eruption  has 
passed  through  to  suppuration  quickly  and  imperfectly. 
In  this  respect  it  is  well  known  that  the  rapidity  of  evolution 
of  a  papule  varies  with  its  size  and  the  depth  of  its  situation 
in  the  skin,  and  the  photos  show  the  effect  of  the  vaccination 
in  bringing  about  this  condition. 

Another  type  illustrated,  Plate  VI,  shows  a  modified 
eruption  which  is  known  under  the  name  of  "  wart-pocks." 
These  pocks  are  chiefly  found  on  the  face,  and  consist  of 


PLATE      IV 


A     MILD     AND      MODIFIED     CASE      OF      SMALL-POX     INFECTED.     SIX      DAYS 
BEFORE    BIRTH.     FROM     ITS    MOTHER 

The  child  was  born  in  hospital  and  successfully  vaccinated  on  the  same  day 
Age  fifteen  days.  Note  the  few  and  scattered  papules  on  this  infant,  the  modihed 
character  is  due  to  the  successful  vaccination  which  was  done  six  days  before 
onset  of  disease.       Photo  taken  on  the  seventh  day  of  eruption. 


PLATE       V 


MODIFIED     CASE     OF     SMALL-POX,    SHOWING     IN     THIS     CASE     A     NEVOID 
CHARACTER     OF     A     CONCURRENT     VACCINATION 

Patient  vaccinated  in  infancy.  Re-vaccinated  oii  the  day  of  appearance  of 
eruption.  A^e  twenty-six  years.  '  In  tins  case  of  small  pox  the  rash  >s  Profuse  but 
extremely  modified,  the  papules  vary  much  in  size  are  superficially  placed  rnatur- 
iuK  rapidly  and  irregularly.  (A)  Superficially  placed  and  rapidly  maturing  papules. 
Photo  taken  on  ninth  day  of  rash. 


PLATE       VI 


A    WELL-MARKED     CASE     OF     SMALL-POX,     SHOWING     CONDITION 
OF     "WART     POCK  ■' 


This  type  of  case,  altliough  somewhat   repulsive  in  appearance,   is  nevertheless 
fairlv  mild  m  its  character,  and  permanent  disfigurement  or   pitting    rarely  follows. 


PLATE       VI I 


SEVERE     CASE     OF     SMALL-POX,      NOT     VACCINATED 
BEFORE     INFECTION. 


Patient  unvaccinated  in  infancy.  Vaccinated  on  the  day  following  the  appear- 
ance of  the  rasli.  .^ge  thirty-four  years.  Ttie  case  sliows  the  effect  of  a  con- 
current vaccination  on  the  course  of  the  disease,  a  rapid  pustulation  and  drying  up 
of  the  rash.  (A)  Atypical  vaccination  scars  with  aborted  vesicle  and  yellow  crust. 
The  clear  areas  around  each  scar  are  not  vesicles,  but  white  or  pinkish  areas  left 
by  the  retraction  of  the  scab.     Photo  taken  on  the  thirteenth  day  of  rash. 


23 

papules  raised  by  the  formation  of  wart-like  masses  of 
granulation  tissue;  the  papules  have  a  fleshy  base,  and 
frequently  the  suppurative  process  is  shortened,  the  pocks 
being  surmounted  by  a  yellow  pustule  about  the  size  of  a 
pin's  head,  which  soon  dries  up,  pitting  is  rare. 

[  Frequently,  a  vaccination  when  performed  after  the 
date  of  infection,  or  even  after  the  onset,  has  the  effect  of 
hastening  the  maturation  and  desiccation  of  the  pustules.y 
For  example,  Plate  VII  shows  a  patient,  un vaccinated  in 
infancy,  who  developed  small-pox  with  a  sudden  and 
violent  onset  and  profuse  rash.  Vaccination  was  performed 
on  the  day  following  the  appearance  of  the  rash,  but  in 
spite  of  this  it  was  thought  the  course  of  the  disease  would 
prove  to  be  severe.  Suppuration  set  in  about  the  usual 
time.  When  the  pustular  stage  ought  to  have  reached  its 
height,  however,  and  the  patient  would  have  been  in  a 
most  critical  condition,  the  temperature  fell,  the  pustules 
at  once  began  to  inspissate  and  form  crusts,  and  then 
rapidly  fell  off.  The  patient  was  free  from  crusts  in  an 
incredibly  short  time.  This  rapid  passage  through  the 
pustular  and  desiccation  stages  was  undoubtedly  due  to 
the  vaccination. 

Ricketts  regards  vaccination  as  having  a  double 
effect  on  the  course  of  the  disease  :  one  effect  is  an  influ- 
ence on  the  extent  of  the  rash,  or  the  numerical  severity ; 
the  other  is  in  the  direction  of  modifying  the  eruption. 
As  age  advances  he  regards  these  two  faculties  as  waning 
together,  but  "  the  protective  influence  against  numicrical 
severity  goes  quicker,  and  the  faculty  to  cause  an  eruption 
to  be  modified  is  retained  for  years  after  the  other  is 
wholly  lost." 

These  points  are  well  illustrated  in  the  series  of 
photographs  which  accompany  this  paper. 


24 


De-vaccination. 

The  length  of  the  period  of  protection  can  be  fairly 
well  gauged  by  an  examination  of  the  appended  Tables. 

The  period  will  vary  a  good  deal  for  each  individual, 
but  from  the  figures  given,  the  highest  resistance  lasts  only 
a  short  time.  After  a  few  years  those  who  become 
susceptible  develop  the  disease  only  in  a  mild  form,  and 
further  on  in  years  greater  severity  manifests  itself  in  the 
type  of  the  disease,  but  no  cases  of  severe  and  fatal  small- 
pox appear  in  this  series  of  cases  until  over  20  years  of  age. 
It  is  evident,  then,  that  following  a  primary  vaccination 
in  infancy,  the  period  of  greatest  protection  in  childhood 
probably  does  not  cover  more  than  three  to  five  years, 
and  after  this,  the  absolutely  preventive  efficiency  of 
vaccination  rapidly  diminishes,  and  cases  of  small-pox 
begin  to  appear  amongst  the  vaccinated.  The  power  to 
modify  the  disease,  however,  still  continues  to  remain 
considerable  until  adolescence,  and  even  into  later  life, 
as  will  be  seen  by  comparing  the  severity  and  the 
percentage  case-mortality  in  different  age-groups  of 
vaccinated  and  unvaccinated  cases. 
(  The  rapid  loss  of  vaccinal  immunity  following  on 
primary  vaccination  in  infancy  is  probably  to  be  explained  x 
by  the  rapid  changes  going  on  during  growth  in  childhood. y' 
The  experience  of  those  who  have  done  much  vaccination 
in  adolescents  or  adults  shows  that  the  protection  afforded 
to  adults  by  re-vaccination  lasts  much  longer  than  the 
same  operation  in  children.  It  is  well  known  that  this 
restored    protection    again    diminishes,    but    much    more 


slowlyw 


An  instructive  example  of  this  gradual  loss  of  pro- 
tection was  shown  in  six  members  of  a  family  (a  mother 


25 


and  five  children)  admitted  to  hospital  suffering  from 
small-pox.  The  disease  attacked  them  all  in  varying 
degrees  of  severity.  They  all  showed  evidence  of  having 
been  vaccinated  in  infancy :  each  of  the  children  had  only 
one  vaccination  scar,  of  |  square  inch  in  area ;  the  mother 
had  three  vaccination  scars,  each  of  the  same  size. 


Case 

Age 

Number 
of  Scars. 

Scar-area 

Character  of 
Disease 

Remarks 

I 

4  years 

I 

§  sq.  inch 

Modified 
discrete, 
very  mild 

Papules  very  few,  not 
over  7-8,  and  not 
vesicular. 

27.. 

I 

ditto 

ditto 

ditto. 

3 

9       ,. 

I 

ditto 

ditto 

Papules  few,  more 
numerous  than  in 
cases  I  and  2,  not 
vesicular. 

4 

12       ,, 

I 

ditto 

Modified 
discrete, 
mild 

Papules  very  numer- 
ous, became  vesicular 
but  soon  dried  up. 

5 

15 

I 

ditto 

ditto 

ditto. 

6 

37 

3 

I J  sq.  inch 

Discrete 

Eruption  more 
marked  than  in  the 
children,  and  passed 
through  the  charac- 
teristic stages. 

This  series  shows  the  gradual  loss  of  the  modifying 
power  in  the  vaccination  as  age  advances,  and  it  is  interest- 
ing as  shown  in  the  same  family,  the  vaccination  scar-area 
being  the  same  in  each  case  except  in  the  mother,  whose 
scar-areas  were  much  larger,  and  therefore  her  protection 
showed  a  proportionally  larger  degree  of  modifying  power. 
Where    age    has   advanced   sufficiently   to    ehminate   the 

4 


26 

previous  vaccinal  protection,  it  will  be  found  that  the 
disease  reverts  to  its  original  type,  as  seen  in  the 
unvaccinated.  In  many  cases,  however,  the  immunity 
conferred  in  infancy  may  persist  in  some  degree  until  late 
in  life,  especially  in  its  power  to  modify  the  disease.  This 
gradual  loss  of  immunity  is  well  shown  in  the  vaccinated, 
in  Chart  A  {page  i6),  where  as  age  advances  the  mild  cases 
become  fewer  in  number,  and  later  in  life  the  severe  types 
of  the  disease,  with  deaths,  begin  to  appear. 


27 


PART    11. 

AN    ANALYSIS    OF    943    CASES    OF    SMALL-POX    (WITH 

PRIMARY     VACCINATION)     IN      RELATION     TO 

SCAR-AREA  AND  SEVERITY  OF  DISEASE. 

The  beneficial  effects  of  vaccination  are  to  be  experienced 
especially  in  those  cases  where  the  process  has  been  carried 
out  in  a  thorough  manner,  and  we  may  conclude  that 
where  vaccine  lymph  has  been  inserted  in  several  places 
it  is  more  effectual  than  when  inserted  in  one  place  only, 
i.e.,  the  larger  the  local  manufactory  of  immunity  or  the 
greater  the  quantity  of  the  specific  material  inserted,  the 
greater  the  degree  of  the  resulting  protection. 

Accordingly,  the  amount  of  immunity  may  be  reckoned 
by  the  superficial  area  of  the  scar. 

An  analysis  of  the  above-mentioned  943  cases  of 
small-pox,  which  had  been  primarily  vaccinated,  was 
carried  out  to  test  the  point.  The  scar-area  was  recorded 
for  each  vaccinated  case  of  small-pox  on  admission  to 
hospital,  according  to  the  method  referred  to  in  the  circular 
letter  of  the  Local  Government  Board  of  England,  issued 
in  1902.  The  diagram  (on  page  28)  represented  the  area 
of  the  scars  in  square  inches,  and  was  used  to  estimate 
it  rapidly,  and  to  record  it.  This  method  of  recording 
superficial  area  is  a  much  better  one  for  estimating  the 
relationship  of  immunity  to  mortality  and  severity,  than 
that  of  counting  the  number  of  scars,  as  was  done  in  the 
valuable  series  of  Dr.  Marson  and  others. 


28 


The  scar-areas  were  arranged  into  age  and  severity 
groups;  an  average  scar-area  was  also  obtained  for  each 
age  period  ;  this  gi-ouping  of  scar-areas  into  severity  and 
age  groups  has  proved  a  most  important  one,  and  some 


"O 

'O 

*o 

"O 

V    J 

Scar-area  Diagram  of  the  Local  Government  Board. 


new  facts  have  come  to  hght  regarding  tlie  changes  which 
scar-areas  undergo. 

A  glance  at  the  figures  in  Table  III  will  illustrate 
clearly  the  arrangement  in  relation  to  severity  and  age. 

The  severity  groups  are  the  same  as  those  used  in  the 
examination  of  the  previous  set  of  small-pox  cases  in 
Part  I. 


29 


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31 


In  the  early  years  of  life  it  is  striking,  as  previously 
stated,  to  find  that  under  two  years  of  age  no  cases  of 
small-pox  are  found  amongst  those  who  have  had  a  primary 
vaccination  in  infancy,*  from  2-5  years  only  very  mild 
cases,  and  from  5-20  years  no  severe  cases  of  small-pox,  or 
deaths,  have  occurred.  ■  In  the  remaining  years  of  life,  it  is 
interesting  to  observe  that  in  almost  every  age  group  the 
mildest  types  of  the  disease  (modified  discrete  and  discrete) 
are  those  with  the  largest  average  scar-area  ;  those  with 
moderate  or  severe  types  of  the  disease  (profuse  and  semi- 
confluent)  have  a  slightly  smaller  scar-area,  at  least  in 
mid-age  periods ;  and  in  those  with  the  most  severe  types 
of  small-pox,  or  where  deaths  have  occurred,  the  scar-area  is 
the  smallest  (see  scar-area  diagram,  page  32).  It  would  be 
well  to  note  that  it  is  a  difficult  matter  to  lay  down  a 
standard  of  severity  for  each  group  of  cases,  especially 
of  the  mildest  types.  The  general  impression  created 
by  the  extent  of  the  eruption  being  the  only  guide,  cases 
on  the  border  line  are  difficult  to  locate,  and  when  the 
cases  in  any  group  are  comparatively  few,  the  more  diffi- 
cult it  is  to  attain  absolute  accuracy. 

It  is  clearly  evident,  however,  that  the  scar-area  of 
the  vaccination  bears  an  inverse  relation  to  the  character 
of  the  eruption  and  intensity  of  the  disease.  An  ex- 
amination of  Table  IV,  A,  will  show  the  average  scar- 
area  for  all  the  cases  at  each  age-period.  It  is  striking 
to  notice  the  gradual  increase  in  this  scar-area  until  20-30 
years,  and  following  on  this,  a  gradual  decline  in  the  size 
of  this  area  as  years  advance. 


*  I  do  not  here  include  cases  of  small-pox  in  infants  (see  chart  and 
photographs  at  the  end)  who  have  been  vaccinated  for  the  first  time  after 
infection  with  the  disease,  and  have  been  in  many  cases  bom  in  a  small-pox 
hospital.  These  are  included  amongst  "concurrent  cases,"  which  are  dealt 
with   in  Part  III.  as  a  separate  class. 


32 


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33 

This  point  has  proved  of  some  interest,  and  an  attempt 
has  been  made  to  explain  it.  It  was  thought  that  in  early 
life,  and  up  to  20  years,  those  persons  who  had  larger 
areas  than  those  recorded  escaped  small-pox.  As  the 
primary  vaccinal  immunity,  however,  gradually  faded, 
these  persons  came  under  the  influence  of  the  disease,  and 
the  recorded  scar-area  of  the  small-pox  cases  increased. 

This  supposition,  however,  ought  to  hold  good  and 
to  extend  into  old  age  ;  this  it  does  not  do,  and  it  will 
therefore  not  explain  the  steady  fall  which  takes  place 
from  30  years  onwards. 

On  reviewing  the  figures  it  becomes  more  probable 
that  the  increase  in  the  scar-area  is  due  to  stretching  of 
the  scar  tissue  on  growth  of  the  body,  reaching  its  height 
at  the  period  20-30  years,  and  as  age  advances  this  scar 
cicatrix  begins  gradually  to  atrophy  and  fade.  This  seems 
clearly  borne  out  by  the  figures,  in  the  tables  and  in  the 
diagram  opposite.* 

In  order  to  test  this  matter  still  further  a  measurement 
was  made  of  the  scar-areas  of  a  certain  number  of  the 
general  population  who  have  never  had  small-pox. 

The  persons  whose  measurements  were  taken  were 
those  found  in  some  of  the  infectious-disease  hospitals, 
where  the  majority  were  children  ;  a  further  series  was 
obtained  in  the  Liverpool  Workhouse,  where  persons  of 
middle  and  advanced  age  were  examined. 

In  all,  the  scar-areas  of  368  persons,  who  never  had 
smaU-pox,  were  measured.  The  figures  in  Table  IV,  B 
{page  30),  and  the  diagram  opposite,  show  the  result.  It 
will  be  evident  that  there  is  a  gradual  increase  in  scar-area 


*  The    suggestion     of    this    explanation    was    made    by   my  colleague, 
Dr.  Stallybrass. 


34 

ill  each  age-period,  from  25  square  inch  under  2  years 
of  age,  to  II  square  inch  at  20-30  years  of  age:  this  is 
the  highest  average  reached ;  the  area  then  gradually  falls 
away  in  size  until  at  60  years  it  is  '47  square  inch. 
This  gradual  increase  until  20-30  years  and  then  a  gradual 
decline  is  a  matter  of  some  importance,  and  is  fuUy  sub- 
stantiated when  we  consider  that  in  all,  including  small- 
pox cases,  the  scar-areas  of  1,311  persons  have  been 
measured. 

Another  interesting  point  to  observe  is  that  the  curve 
formed  by  the  average  vaccination  scar-area  of  the  general 
population  which  is  shown  on  the  attached  diagram,  is  a 
higher  one  at  all  age-periods  than  that  obtained  from  those 
who  have  been  attacked  by  small-pox.  This  is  another 
point  in  favour  of  the  value  of  large  vaccination  areas  in 
protecting  the  individual  from  the  disease. 

In  many  previous  investigations  on  the  influence  of 
scar-area  on  small-pox,  the  cases  with  the  scar-areas  of 
approximately  the  same  size  have  been  taken  and  grouped, 
and  shown  to  be  associated  with  varying  degrees  of 
severity ;  but  no  account  seems  to  have  been  taken  of  the 
age  of  the  patients,  nor  was  the  interesting  fact  realized 
that  the  scar-area  in  the  individual  varies  at  different 
periods  of  life.  In  future  comparisons  t^is  point  will  have 
to  receive  more  consideration. 


35 


PART    III. 

OBSERVATIONS    ON    THE    INTERACTION    OF 
CONCURRENT    VARIOLA    AND    VACCINIA. 

It  has  been  abundantlj^  shown  by  the  experiments  of 
Thiele  and  Ceely,  and  more  recently  by  Klein  and  Copeman, 
that  cow-pox  or  vaccinia  may  be  considered  as  an  attenuated 
descendant  of  small-pox ;  and  in  connection  with  this  close 
relationship,  if  not  absolute  identity,  of  these  two  affec- 
tions, the  examination  of  the  following  series  of  75  cases 
of  smaU-pox  with  a  concurrent  vaccination  will  prove  of 
interest.  The  cases  have  been  collected  during  the  past 
ten  years  in  the  City  and  Port  of  Liverpool.  Many  of 
them  were  persons  who  were  landed  incubating  or  suffering 
from  the  disease,  and  were  removed  to  the  Port  Isolation 
Hospital;  these  were  chiefly  cattle-men  from  Boston,  who 
landed  incubating  small-pox  during  the  severe  outbreak 
in  that  city  in  1902-3. 

The  cases  may  be  examined  in  the  light  of  the  relative 
effects  produced  on  one  another  by  each  of  these  condi- 
tions :  (i)  As  regards  the  success  of  the  vaccination 
when  performed  subsequently  to  infection  with  small-pox ; 
and  (2)  As  regards  the  effect  of  the  vaccination  on  the 
course  and  severity  of  the  disease.  Cases  of  concurrent 
variola  and  vaccinia  have  rarely  been  given  the  prominence 
which  they  deserve,  and  it  was  with  this  object  that  the 
present  series  was  collected.  The  series,  then,  gives 
information  of  the  effect   of  vaccination  or  re-vaccination 


36 

performed  after  exposure  to  infection  and  running  con- 
currently with  the  course  of  the  disease. 

The  Success  of  the  Vaccination. 

The  success  of  the  process  may  first  be  considered, 
and  the  series  may  be  conveniently  divided  into  two 
groups,  viz.  :  (i)  Those  who  have  never  been  vaccinated 
until  infected  with  small-pox,  Chart  B  {page  37) ;  (2)  Those 
who  have  been  primarily  vaccinated  in  infancy,  Chart  C. 
{page  38). 

On  examining  the  charts  it  will  be  seen  that  the 
period  of  twelve  days  has  been  taken  as  the  duration  of 
the  incubation  period  :  this  has  been  found  to  be  prac- 
tically correct  for  all  the  cases;  they  were  all  carefully 
investigated  both  as  to  the  symptoms  of  onset  and  initial 
rash,  and  found  to  correspond  to  the  period  set  forth  in 
the  charts. 

It  cannot  be  disputed  that  possibly  cases  may  occur 
with  a  day  or  so  longer  or  shorter  incubation  period,  but 
very  few  of  this  sort  can  be  quoted  as  evidence  for  an 
incubation  period  other  than  that  stated.  The  average 
generally  accepted  and  acted  on  for  public  health  adminis- 
tration is  twelve  days,  a  period  which  has  been  found  to 
work  out  well  in  practice,  the  rash  appearing  about  three 
days  after  initial  symptoms. 

The  first  point  to  notice  in  connection  with  those 
cases  is  that  all  have  been  exposed  to  the  infection  of 
small-pox,  and  all  with  two  exceptions  {see  Chart  B), 
have  contracted  and  developed  signs  of  the  disease.  These 
two  exceptions  were  cases  of  children  born  in  hospital  of 
variolous  mothers,  vaccinated  within  24  hours  of  birth, 
and  were  under  daily  observation  {see  Plate  VIII). 


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39 

The  cases  have  been  set  out  showing  those  vaccinated 
and  re- vaccinated  on  different  days :  first,  during  the  period 
of  incubation,  and  second,  after  the  onset  of  symptoms, 
and  even  until  three  days  after  the  rash  had  appeared. 
It  is  unnecessary  to  say  that  vaccination  efficiently  per- 
formed in  susceptible  people  before  exposure  to  infection  of 
small-pox  will,  almost  without  exception,  prove  successful, 
and  will  protect  the  individual  from  developing  any 
symptoms  or  signs  of  the  disease. 

Vaccination  during  Incubation. — On  examining  the 
charts  it  will  be  found  that  all  the  vaccinations  and  re- 
vaccinations  have  been  successful  if  performed  during  the 
incubation  period  and  even  up  to  the  day  of  onset  of  sym- 
ptoms. When  the  term  "successful"  is  used,  it  must  be 
understood  that  the  phenomena  at  the  site  went  through 
the  typical  and  normal  course  of  human  vaccination. 
These  phenomena  may  be  shortly  described  as  follows  : 
a  sUght  inflammatory  reaction  may  appear  at  the  site,  but 
nothing  of  moment  occurs  until  the  end  of  the  third  day, 
when  firm,  fiat,  elevated  papules  appear  at  the  site  of  the 
operation  ;  these  become  surrounded  by  a  halo  of  hyper- 
aemia.  Vesicles  appear  on  the  fifth  or  sixth  day,  and  are 
especially  marked  at  the  periphery.  These  are  filled  with 
clear  lymph,  and  the  zone  of  hypersemia  has  increased, 
with  acute  swelling  ;  the  vaccination  is  red  and  firm,  and 
the  axillary  glands  may  be  swollen.  Cloudiness  begins  to 
appear  in  the  vesicles  on  the  eighth  day,  and  subsequently 
they  become  opaque  and  yellow.  The  height  of  the 
vaccination  is  reached  on  the  ninth  or  tenth  day,  and  from 
this  date  there  are  signs  of  rapid  desiccation.  The  changes 
most  characteristic  of  vaccination  are  found  during  the 
third,  fourth,  fifth,  and  sixth  days. 

The      successful     vaccinations     and     re-vaccinations 


40 

recorded  in  the  charts  were  therefore  more  or  less  of  the 
above-described  characters,  and  they  all  showed  the 
characteristic  ring  or  vesicle  situated  on  a  papule  and 
going  on  to  suppuration  and  desiccation.  {See  Plates  IX 
and  X.) 

Vaccination  after  onset  of  the  disease. — -The  operations 
performed  subsequently  to  the  onset  of  symptoms  were 
unsuccessful  {see  Plates  XI,  and  XI I).  The  papule  did  not 
reach  its  typical  character,  the  areola  may  not  have 
developed  and  vesicles  did  not  appear,  or  the  vaccine 
pocks  developed  a  nsevoid  character  or  appeared  stunted 
in  development,  and  rapidly  dried  up.  It  must  be  granted, 
however,  that  in  some  of  the  cases  the  organisms  introduced 
into  the  system  may  have  had  some  modifying  effect  on 
the  course  of  the  disease,  although  no  typical  reaction 
occurred.  This  point  will  be  referred  to  later.  In  other 
cases,  and  notably  in  those  vaccinated  late  in  the  disease, 
no  reaction  appeared  at  the  site,  or  simply  a  slight  trau- 
matic reaction  occurred.  It  will  be  well  to  mention  at 
this  point,  that  fallacious  conclusions  may  be  drawn  from 
the  appearance  of  the  vaccination  area  under  the  following 
conditions.  It  is  well  known  that  an  especially  abundant 
eruption  is  not  infrequently  observed  on  parts  of  the  body 
which,  before  the  eruption  appears,  have  been  affected 
by  mechanical  or  inflammatory  irritation  {see  Plate  XIII). 
Such  areas  of  eruption  are  sharply  marked  off,  and  take  on 
strikingly  the  form  of  the  area  of  irritation,  e.g.,  a  patient 
who  has  been  previously  carrying  heavy  bags  on  his  back 
will  show  a  more  profuse  eruption  on  his  shoulders,  or 
the  irritation  in  the  front  of  the  neck  caused  by  a  collar 
stud  will  cause  a  little  crop  of  vesicles  to  appear  at  this 
point.  Other  examples  might  be  mentioned,  such  as  an 
eruption  round  the  thigh  where  a  garter  has  caused  pressure. 


PLATE       VIII 


MOTHER      SUFFERING     FROM      SMALL-POX      NURSING      HER 
SUCCESSFULLY     VACCINATED     BABY. 


Mother  aged  twenty-five  years.  Vaccinated  in  infancy.  Baby  born  in  liospital 
and  successfully  vaccinated  on  the  following  day.  No  signs  or  symptoms  of 
small-pox  appeared  in  the  child,  which  was  nursed  by  the  mother  throughout  her 
own  illness  in  hospital,  and  discharged  after  six  weeks,  (A)  Infant's  successful 
vaccination.     Photo  taken  on  the  ninth  day  of  the  vaccination. 


PLATE       IX 


A     VERY     MILD     AND     MODIFIED     CASE     OF     SMALL-POX 


Patient  vaccinated  for  the  fir^  time  seven  days  before  onset  of  symptoms. 
Age  seven  years.  The  successful  vaccination  has  modified  exceedingly  the  disease, 
so  that  the  papules  are  comparatively  few  in  number.  This  boy  was  infected  by 
his  sister,  who  was  unvaccinated,  and  had  a  most  severe  attack  of  small-pox. 
Photo  taken  on  the  sixth  dav  of  rash. 


PLATE      X 


A     MODIFIED     CASE     OF     SMALL-POX 


Patient  vaccinated  in  nilancv.  Ke-\accinatecl  lour  days  before  onset  of  disease. 
Age  twenty-six  years.  This  patient  shows  a  successful  re -vaccination  which  is 
typical  in  appearance. 


PLATE      XI 


A     MILD     AND     MODIFIED     CASE     OF     SMALL-POX 

Patient  vaccinated  in  infancy.  Ke-vaccinated  on  tlie  day  after  onset  of 
symptoms.  Age  twenty-four  years.  This  patient  shows  a  vaccination  which  is 
atypical  in  character. 


PLA  TE      XII 


SEVERE     ATTACK     OF     SMALL-POX     IN     A     PERSON     WITHOUT 
PRIMARY     VACCINATION     IN     INFANCY 


Patient  iinvaccinated  in  inlancy.  Vaccinated  lur  first  time  un  the  fourth  day 
of  the  disease.  Age  twenty-seven  years.  The  plate  shows  that  the  eruption,  as 
shown  on  the  upper  arm,  was  very  profuse  over  the  body  ;  the  vaccination  having 
been  performed  rather  late  was  atypical  and  naevoid  in  character.  Photo  taken 
three  weeks  after  the  appearance  of  the  rash. 


PLATE      XIII 


O'  """T;''  ^^'^M^H 

\' 

-^, 

'  i' 

/,*m-_i 

7 

c  > 

\.^ 

X    . 

A     VERY     MODIFIED     CASE     OF     SMALL-POX 


Infantile  vaccination  did  not  take.  Re-\'accinated  successfully  six  days  before 
onset.  Age  tweh'e  years.  This  case  is  interesting  as  showing  that  the  inflam- 
matory areola  around  the  vaccination  area  has  determined  a  numerous  crop  (A)  of 
small-pox  vesicles  to  appear.  The  rash  is  well  marked  and  confined  more  particu- 
larly to  the  face.     Photo   taken  on   the  sixth   day  of  the  rash. 


PLATE      XIV 


A     CASE     OF     SMALL-POX     OF     MODERATE     SEVERITY 


The  patient  was  a  Kiissian  inimi{,'rant,  and  had  been  very  poorly  vaccinated  in 
infancy,  the  scar-area  oiilv  appi  cixiinatinf,'  one-tenth  square  inch.  He  remained 
critically  ill  for  a  long  timr,  luit  ultimately  recovered.  Aged  seventeen  years. 
A  scratch  on  the  right  hand  caused  by  the  patient  breaking  a  pane  of  glass  has 
determined  a  confluent  crop  of  papules  to  develop  on  each  side  of  the  scratch. 
(A)  Confluent  crop  of  vesicles  at  scratch. 


PLATE       XV 


A    MILD    AND     MODIFIED    CASE    OF    SMALL-POX 


The  patient  was  \accinated  n\  iiilancy.  Re-vaccinated  witliout  result  five  days 
after  onset  of  the  disease.  Age  twenty -five  years.  .\  confluent  eruption  is  seen  on 
tlie  foreliead,  due  to  spirit  compress  used  by  the  patient  to  reUeve  headache. 
The  patient  was  vaccinated  five  days  after  onset  of  the  disease  without  any  local 
result.  (A)  Unsuccessful  attempt  at  vaccination.  Photo  taken  on  fifth  day  of 
the  rash. 


PLATE      11 


A     CASE     OF     SMALL-POX     OF     MODERATE     SEVERITY 


Patient  vaccinated  in  infancy.  Ke-\accinated  successfully  six  days  before  erup- 
tion appeared.  Age  twenty-four  years.  Note  that  in  this  case  the  rash  is  more 
profuse  than  in  Plate  I ,  but  the  distribution  is  the  same.  The  anterior  triangle  of 
neck  is  relatively  free.  The  re-vaccination  is  well  shown,  and  there  is  a  charac- 
teristic crop  of  small-pox  vesicles  situated  on  the  inflammatory  areola  around  the 
vaccination  site.     Photo  taken  on  fifth  day  of  rash. 


PLATE     XVI 


^^^^^^^^^t^^ 

m- 

^^^^HJ^6C            i 

>. 

I 

^ 

f 

A     SEVERE     CASE     OF     SMALL-POX 


The  patient  was  vaccinated  in  infancy.  Re-vaccinated  without  result  five  days 
after  onset  of  disease.  .\ge  thirty-five  years.  The  case  shows  that  the  disease  may 
become  very  severe  in  those  who  liave  lost  immunity  with  advancing  years:  this 
patient  is  ten  years  older  than  that  shown  in  Plate  XV.  The  result  of  vaccina- 
tion was  atypical  and  of  a  nsevoid  character.  Around  the  areas  are  irregular  rings 
of  confluent  small-po.\  vesicles  and  pustules,  which  give  an  erroneous  appearance 
of  success.     Photo  taken  on  the  eighth  day  of  the  eruption. 


41 

or  a  confluent  eruption  on  each  side  of  a  scratch  on  the 
hand  {see  Plate  XIV).  Similar  phenomena  can  be  seen 
after  chemical  or  other  irritation  {see  Plate  XV). 

When  a  vaccination  has  been  performed,  therefore, 
from  the  day  of  onset  onwards  until  the  rash  appears,  the 
inflammation  and  irritation  due  to  the  operation  and  the 
slight  local  reaction  which  occurs  may  cause  a  crop  of 
small-pox  vesicles  to  appear  around  the  area.  This  is 
especially  the  case  in  severe  or  confluent  small-pox,  but 
may  be  also  seen  when  the  rash  is  very  sparse  on  the  rest 
of  the  body.  These  vesicles,  especially  in  severe  cases, 
may  coalesce  so  as  to  form  a  ring  around  the  vaccination 
site,  and  give  rise  to  a  false  appearance  of  success  of  the 
operation  {see  Plates  XVI  and  XVII).  Many  cases, 
therefore,  said  to  be  successfully  vaccinated,  are  really  due 
to  coalescence  of  small-pox  vesicles  and  pustules  around 
the  area  of  the  vaccination.  This,  I  am  convinced,  is  the 
case  ;  it  is  only  likely,  however,  to  give  rise  to  doubt  in 
cases  of  severe  or  confluent  small-pox  where  the  eruption 
is  profuse. 

Clinical  Society's  Report. — These  observations  were 
completed,  when  attention  was  drawn  to  a  report,  published 
in  1878,  of  a  Committee  of  the  Clinical  Society  of  London, 
formed  to  investigate  the  periods  of  incubation,  contagious- 
ness, etc.,  of  small-pox  In  this  report  there  are  twenty- 
two  cases  of  concurrent  variola  and  vaccination  recorded 
by  Dr.  Birdwood,  of  the  Metropolitan  Asylums  Board's 
Hospital.  These  cases  are  incomplete  in  their  details,  but 
I  have  taken  twenty  of  them  which  can  fairly  well  be  used 
in  comparison.  These  have  been  arranged  in  the  same 
type  of  chart  as  that  of  the  present  paper,  and  it  is 
surprising  to  find  a  very  close  agreement  {Chart  D,  page  42). 

It    will    therefore    be    abundantly    evident    from    the 

5 


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43 

charts  and  photographs  that  the  operation  of  vaccination 
performed  at  any  time  during  the  incubation  period  will 
be  successful.  This  may  be  true  even  during  the  first 
period  of  onset,  but  if  carried  out  subsequently  to  the 
initial  symptoms,  the  vaccination  will  not  be  successful  or 
typical  in  its  appearance.  Dr.  Birdwood  states  that  he 
has  "  only  found  one  vaccination  which  was  successful  if 
vaccinated  on  the  day  of  eruption  or  after."  In  my  opinion, 
and  for  the  reasons  which  have  been  given,  the  case  was 
probably  not  a  successful  one,  the  appearance  of  success 
having  been  given  by  the  coalescence  in  a  confluent  case 
of  the  vesicles  and  pustules  around  the  inflammatory  zone 
of  vaccination.  In  the  same  report,  Dr.  Colclough,  who 
was  at  that  time  Assistant  Medical  Officer  at  the  hospital 
ships,  in  a  note  states,  "  In  the  few  instances  in  which  I 
have  vaccinated  patients  on  their  admission,  when  the 
eruption  has  been  in  the  macular  or  papular  stages,  the 
re- vaccination  has  failed,  and  the  reports  of  over  fifty  cases 
of  re-vaccinations  (taken  from  the  case  books),  in  various 
stages  of  eruption,  coincide  with  my  few  instances." 

I  have  often  heard  the  statement  made  by  medical 
men,  that  when  persons  have  been  vaccinated  and  the 
operation  is  not  proving  successful,  there  is  a  likelihood 
they  will  develop  small-pox,  or  that  these  cases  ought  to 
be  watched  and  isolated.  In  my  opinion  it  is  in  cases 
recently  vaccinated  which  show  evidences  that  the  opera- 
tion will  probably  be  successful,  and  where  there  is  low 
immunity,  that  small-pox  is  likely  to  develop ;  these 
cases  require  to  be  kept  under  surveillance.  Some  time 
ago,  a  vessel  arrived  in  Liverpool  having  had  a  case  of 
smaU-pox  on  the  voyage  ;  the  man  died  and  was  buried  at 
sea  five  days  before  reaching  Liverpool.  All  the  crew  were 
vaccinated  on  arrival ;  one  of  them,  who  assisted  in  burying 


44 

this  man,  developed  a  very  mild  rash  of  small-pox  ten  days 
after  vaccination  and  the  arrival  of  the  ship  ;  his  vaccina- 
tion had  taken  in  three  places,  and  showed  typical  vesicles 
and  other  associated  signs.  Therefore,  assuming  that  the 
vaccinations  have  been  properly  performed  with  active 
lymph,  the  cases  to  be  watched  more  particularly  are  those 
which  show  signs  of  the  vaccination  "  taking." 

Influence  of  Concurrent  Vaccination  on  the 
Course  of  the  Disease. 

Another  aspect  of  the  subject  may  now  be  studied 
with  advantage,  namely,  the  influence  of  this  vaccination 
on  the  course  and  severity  of  the  disease  {see  Charts  B,  C, 
and  D). 

The  degrees  of  severity  have  been  classified  for  con- 
venience into  three  groups  :  Column  i  represents  a  mild 
attack  of  the  disease  ;  Column  2  a  moderate  or  severe  attack ; 
and  the  very  severe  group  is  recorded  under  Column  3  : 
this  group  also  includes  deaths,  but  these  are  shown 
individually  in  the  body  of  the  table. 

Chart  B. — On  an  examination  of  the  thirty  cases 
without  a  primary  vaccination  in  Chart  B,  it  will  be  seen 
that  of  Cases  i  to  5,  vaccinated  within  the  first  three 
days  of  infection,  two  developed  no  symptoms  or  signs  of 
the  disease,  whilst  three  had  an  exceedingly  mild  attack 
after  an  initial  malaise.  In  these  latter  onlj'  a  few  papules 
appeared,  which  never  became  vesicles,  but  simply  died 
away  ;  in  these  aborted  cases  the  small-pox  had  just  over- 
come the  protective  effect  of  the  vaccination. 

Tracing  the  cases  further  on  in  the  disease,  we  find 
that  the  type  becomes  more  or  less  severe,  according  to 
individual    susceptibility,    until    we    come    to    those    of 


45 

moderate  severity,  vaccinated  from  the  seventh  day  of 
infection  up  to  the  onset ;  following  on  this  the  cases 
vaccinated  after  the  onset  of  the  disease  will  be  seen  to 
have  been  of  the  very  severe  t^'pe,  three  of  them  ending 
fatally,  showing  that  cases  vaccinated  at  the  stage  of  onset 
and  after  the  rash  has  appeared,  have  much  less  chance  of 
benefiting  by  the  vaccination. 

Chart  C. — If  attention  be  now  turned  to  Chart  C, 
showing  forty-five  cases  of  small-pox  with  a  primary 
vaccination  in  infancy,  it  is  of  interest  to  find  that  in  this 
group  the  effect  of  the  primary  vaccination  is  shown  on  the 
course  of  the  disease :  the  primary  vaccination  along  with 
the  re-vaccination  performed  concurrently  has  greatly 
assisted  in  modifying  the  severity  of  the  disease. 

Further,  it  will  be  noticed  that  in  this  chart  of  cases 
which  show  a  primary  vaccination,  there  are  no  cases  found 
vaccinated  on  the  day  of  infection  or  on  the  first  three  days 
following.  This  may  be  accounted  for  by  the  fact  that  the 
double  vaccination,  i.e.,  primary  and  re- vaccination,  has 
prevented  the  onset  of  symptoms  or  appearance  of  rash  in 
persons  re-vaccinated  on  these  days,  and  therefore  I  have 
been  unable  to  obtain  small-pox  cases  to  place  on  the 
chart  in  the  position  corresponding  to  these  days  ;  this 
view  is  also  supported  by  the  chart  of  Dr.  Birdwood's 
cases.  It  may  be  remarked,  however,  that  the  number 
of  cases  is  smaU  to  draw  such  final  conclusions  ;  still,  I 
draw  attention  to  the  fact  as  being  one  of  probably  some 
importance  from  an  administrative  standpoint. 

On  examining  the  cases  re-vaccinated  before  the  onset 
of  symptoms,  it  will  be  seen  that  in  nearly  all  the  disease 
was  of  a  mild  or  very  mild  type.  Taking  this  portion,  i.e., 
during  incubation  period,  of  the  series  in  Chart  C,  there 
are    only    four    cases  out   of   twenty-seven  in  which   the 


46 

eruption  may  be  considered  as  of  moderate  or  severe 
character. 

The  cases  vaccinated  after  the  onset  of  the  disease, 
and  subsequently  to  the  appearance  of  the  rash,  showed  a 
more  pronounced  type ;  in  this  case  most  of  the  patients 
had  the  disease  in  a  moderate  or  severe  form. 

When  it  is  stated  that  the  vaccination  or  re- vaccination 
was  unsuccessful  as  an  operation,  it  must  not  be  understood 
that  the  modified  organisms  implanted  in  the  system  did 
not  exercise  any  appreciable  modifying  effect.  Case  No.  28 
amongst  the  unvaccinated  (Chart  B)  illustrates  this  point. 
A  lady,  unvaccinated  in  infancy,  contracted  small-pox 
abroad,  and  was  vaccinated  one  day  after  the  appearance 
of  the  rash  ;  a  slight  traumatic  reaction  occurred  at  the 
site  of  vaccination,  with  ill-defined  papule  and  aborted 
vesicle,  forming  a  yellow  crust,  which  was  quite  atypical. 
The  case  passed  through  a  severe  attack  ;  towards  the 
twelfth  to  fourteenth  day  of  the  disease,  however,  when  the 
suppurative  stage  ought  to  have  been  at  its  height,  it  was 
surprising  to  find  the  pustules  rapidly  drying  and  falling 
off,  so  that  within  a  day  or  so  they  had  entirely  gone  ;  the 
resulting  scars  were  totally  absent,  and  only  marked  staining 
remained,  which  disappeared  under  a  year,  and  no  trace  of 
the  disease  can  now  be  seen  after  some  years.  The  case 
was,  to  my  mind,  a  convincing  proof  of  the  value  of 
vaccination  done  subsequently  to  onset  of  symptoms,  and 
the  operation  ought  therefore  to  be  performed  on  all  cases 
admitted  to  hospital.  Other  cases,  not  so  striking,  can  be 
quoted. 

The  remarkable  antagonism  of  these  two  diseases  can 
only  be  explained  by  a  consideration  of  the  question  of 
immunity  or  concurrent  immunities.  It  may  suffice  to 
say  that  in  small-pox  with  a  concurrent  vaccination,  it  is  a 


47 

race  between  the  virulent  and  the  modified  organisms  ; 
the  less  virulent  and  the  more  saprophytic  forms  grow 
faster  and  produce  immunity  more  quickly  than  the 
more  virulent  ones.  Protection  is  not  acquired  at  any 
particular  time,  but  there  is  a  gradual  accumulation  of 
immunity  in  the  blood,  which  usually  shows  itself  to  be 
completed  by  the  beginning  of  the  second  week  after 
vaccination. 

It  would  seem  from  an  examination  of  the  charts,  that 
nine  days  after  vaccination  is  the  period  required  to  give 
real  evidence  of  the  increasing  protection  against  small-pox. 

It  is  therefore  evident  that  the  intensity  of  the  disease 
bears  an  inverse  ratio  to  the  period  of  vaccination  ;  the 
later  the  disease  appears  after  vaccination,  the  more 
opportunity  for  the  vaccination  to  be  successful  and  develop 
its  counteracting  immunity;  when  the  small-pox  appears 
early  in  the  course  of  a  vaccination,  the  more  severe  is 
the  course  of  the  disease. 

On  referring  to  Chart  B  of  unvaccinated  cases,  it  will 
be  seen  that  cases  of  small-pox  vaccinated  within  three 
days  after  infection  will  develop  very  slight  or  no  sym- 
ptoms of  small-pox ;  and  a  reference  to  Chart  C  shows  no 
cases  occurring  within  the  first  three  days.  One  may 
safely  infer,  therefore,  that  vaccinations  performed  within 
the  first  three  days  of  infection  in  persons  with  a  primary 
vaccination  will  not  develop  small-pox,  and  in  those  who 
are  unvaccinated  the  chances  are  that  the  disease  will  not 
develop  ;  or,  in  other  words,  vaccination  requires  nine 
days  to  develop  an  immunity  which  will  absolutely 
prevent  or  minimise  an  attack  of  small-pox. 


48 


Concurrent    Cases    amongst    Infants. 

An  instructive  series  of  concurrent  cases  is  shown  in 
the  following  Chart  E,  with  its  accompanying  photographs. 
The  series  sets  out  in  tabular  form  seven  cases  of  small-pox 
in  infants  with  concurrent  vaccination.  The  majority  of 
these  were  born  in  hospital  of  variolous  mothers,  and 
vaccinated  within  a  few  days  of  infection ;  two  are  shown 
to  have  been  infected  in  utero. 

It  will  be  seen  that  Cases  i  and  2  [Plates  XVIII  and 
XIX),  infected  with  small-pox  on  the  da}^  of  birth  and 
the  day  following  respectively,  were  vaccinated  within 
twenty-four  hours,  with  entire  absence  of  development 
of  any  symptoms  or  signs  of  the  disease ;  and  the 
mothers  continued  to  nurse  these  children  until  they 
were  convalescent  and  discharged ;  in  these  cases  the 
vaccinations  were  entirely  successful  and  absolute  pro- 
tection was  afforded. 

Cases  3  and  4  (Plates  XX  and  XXI)  were  vaccin- 
ated later  in  the  incubation  period  of  the  disease.  Case  3 
was  vaccinated  at  the  end  of  the  third  day  of  incubation, 
and  had  a  very  mild  attack,  as  illustrated  in  the  photo- 
graph. The  eruption  was  very  sparse  and  scattered,  and 
the  individual  papules  rapidly  passed  through  the  pre- 
liminary stages  to  pustulation ;  this  is  one  of  the  charac- 
teristic effects  of  vaccination.  Case  4  was  vaccinated  on 
the  fourth  day  of  incubation,  and  had  a  very  mild  attack. 

Case  5  {Plate  XXII)  was  vaccinated  on  the  fifth  day 
of  incubation,  the  day  following  its  birth,  and  showed 
a  more  profuse  eruption  of  small-pox.  This  baby  was 
infected  in  utero.  The  mother's  rash  appeared  on 
December  12th,  while  the  child's  eruption  appeared  on 
December  27th,  exactly  fifteen  days  later. 


49 

Case  6  (Plate  XXIII),  four  months  old,  and  un- 
vaccinated,  was  infected  with  small-pox  on  March  30th  ; 
owing  to  various  circumstances  in  connection  with  the 
illness  of  the  mother  and  consequent  delay  in  the 
reporting  of  the  case,  the  baby  was  not  vaccinated 
until  the  eighth  day  after  infection;  the  eruption  was 
profuse,  but  complete  recovery  took  place. 

Case  7  was  a  baby  infected  on  February  28th  in  utero. 
The  mother's  rash  appeared  on  that  day;  the  child  was 
born  on  March  6th  and  vaccinated  on  March  gth.  The 
disease  was  of  very  severe  type  and  death  ensued.  The 
vaccination  in  this  case  was  carried  out  too  late  to  have 
an  opportunity  of  neutralizing  or  modifying  the  course  of 
the  small-pox. 

Without  undue  repetition  of  perfectly  obvious  facts, 
it  will  not  be  out  of  place  to  again  point  out  that  the 
non-development  of  small-pox  or  its  extraordinarily  mild 
character  in  those  infants  of  the  above  series  which  were 
vaccinated  in  good  time,  contrasts  markedly  with  what  is 
shown  in  Chart  A  {page  16),  as  occurring  amongst 
unvaccinated  children,  where  a  50  per  cent  mortality  is 
shown  as  a  result  of  the  neglect  of  this  obvious  precaution. 

Fortunately  it  has  been  possible  to  insert  two  plates 
{XXIV  and  XXV),  which  will  bear  out  the  above  obser- 
vation and  serve  as  contrasts  with  the  foregoing  series. 


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PLATE      XVII 


A     SEVERE     CASE     OF     SMALL-POX,      UNVACCINATED     IN     INFANCY 


The  patient  was  vaccinated  for  the  first  time  unsuccessfully  three  days  after 
onset  of  symptoms  and  after  the  appearance  of  the  rash.  Age  forty-three  years. 
The  result  of  the  vaccination  has  been  unsuccessful,  and  the  appearance  of  the 
vaccination  areas  compares  with  Plate  XVI.  Photo  taken  on  the  sixth  day  of 
the  eruption. 


PLATE      XV 1 11 


l.-A  CHILD  SUCCESSFULLY  VACCINATED  ON  THE  DAY  OF  BIRTH 
AND  NURSED  BY  ITS  MOTHER.  WHO  HAD  SMALL-POX.  THROUGH- 
OUT    HER     ILLNESS     OF     SIX     WEEKS     IN     A     SMALL-POX     HOSPITAL 


Child  born  January  15th,  vaccinated  successfullv  on  January  16th.  Mother 
developed  small-pox  rash  on  January  16th,  and  nursed  her  child  in  hospital  until 
discharged.     No  development  occurred  in  the  child. 


PLA  TE      XIX 


-MOTHER      SUFFERING      FROM      SMALL-POX      NURSING      HER 
SUCCESSFULLY     VACCINATED     BABY 


Mother  aged  twenty-five  years.  Vaccinated  in  infancy.  Baby  born  in  hospital 
and  successfully  vaccinated  on  the  following  day.  No  signs  or  symptoms  of 
small-pox  appeared  in  the  child,  which  was  nursed  by  the  mother  throughout  her 
own  illness  in  hospital,  and  discharged  after  si.\  weeks.  (A)  Infant's  successful 
vaccination.     Photo  taken  on  the  ninth  day  of  the  vaccination. 


PLATE      XX. 


-AN     EXCEEDINGLY     MILD     AND     MODIFIED     ATTACK 
OF     SMALL-POX 


Child  born  April  I'Jth,  vaccinated  successfully  April  -!ind,  three  days  after 
infection.  Mother  developed  small-pox  rash  on  April  19th,  and  nursed  the  child 
throughout  her  illness.  The  baby  developed  a  small  number  (twenty)  of  small- 
pox papules  scattered  on  its  body.     Photo  taken  on  the  third  day  of  the  rash. 


PLATE      XXI 


Case    4— A     VERY     MILD     AND     MODIFIED     CASE     OF     SMALL-POX 

Child  aged  three  months,  was  vaccinated  successfully  four  days  after  infection 
with  small-pox,  i.e.,  eight  days  before  onset.  The  child  developed  a  very  mild 
attack  of  small-pox;  not  more  than  eight  or  nine  papules  on  the  face,  and  about 
twenty  on  the  body. 


PLATE       XXII 


-ANOTHER     CASE     OF     MILD     SMALL-POX     IN      AN      INFANT 
SUCCESSFULLY     VACCINATED     BEFORE     ONSET 


Child  aged  fifteen  days,  born  on  December  16th,  and  successfully  vaccinated 
five  days  after  infection  from  the  mother,  whose  rash  appeared  on  December  12th. 
The  child  de\'eloped  a  mild  attack  of  small-pox  with  sparse  eruption.  It  will  be 
noticed  that  the  later  the  day  of  vaccination  after  infection,  the  more  severe  the 
character  of  the  disease.  Compare  Plates  A'.V,  XXI,  and  XXHl.  Photo  taken 
on  sixth  day  of  the  rash. 


PLATE      XXIII 


.-ANOTHER     CHILD.     SHOWING     A     MILD    AND     MODIFIED     ATTACK     OF 
SMALL-POX.     AND     VACCINATED     FOUR     DAYS     BEFORE     ONSET 


Child  aged  four  months,  was  successfully  vaccinated  eight  days  after  infection 
with  small-pox.  The  patient  developed  a  modified  attack  of  small-pox,  but  the 
eruption  was  much  more  numerous  and  pronounced,  and  papules  of  larger  size, 
than  in  any  of  the  previous  cases.       Photo  taken  on  eighth  day  of  the  rash. 


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51 


Conclusions. 
The  following  conclusions  may  be   drawn   from  the 


Part  I  :— 

{a).  That  the  case  mortality  in  the  natural  disease, 
i.e.,  in  the  un vaccinated,  which  ranges  from 
approximately  25  to  40  per  cent,  has  been 
reduced  by  the  power  of  vaccination  to  about 
3  per  cent  in  those  who  have  been  well 
vaccinated. 

[b).  That  in  the  unvaccinated,  persons  at  the  extremes 
of  life,  mainly  children  under  10  years  of  age 
and  old  people,  are  those  who  suffer  most,  the 
case  mortality  reaching  as  high  as  50  per  cent. 
In  the  previously  vaccinated,  no  cases  are 
recorded  occurring  under  three  years  of  age; 
under  twenty  years  of  age  no  deaths  are 
recorded,  but  as  age  advances  the  vaccination 
gradually  loses  its  protective  and  modifying 
power. 


(c).  That  even  when,  owing  to  age,  and  consequent 
gradual  loss  of  vaccinal  immunity,  vaccination 
'  is  unable  to  stop  the  development  of  the  disease, 
it  may  modify  the  extent  and  character  of  the 
eruption  to  such  a  degree  as  to  make  it  so 
exceedingly  mild  that  in  many  instances  the 
disease  may  be  undetected. 
\  7 


52 

Pari  II  :— 

[d).  That  the  scar-area  of  vaccination  has  an  important 
bearing  on  the  severity  of  the  disease  ;  the 
larger  the  area,  the  milder  the  character  of  the 
disease. 

[e).  That  the  vaccination  scar-area  gets  larger  as  age 
advances  until  the  20-30  years  age-period  is 
reached ;  it  then  gradually  becomes  smaller, 
in  all  probabiUty  owing  to  atrophy  of  the  scar 
tissues. 


Part  III  :— 

(/).  That  vaccination  performed  subsequentlj^  to 
infection  with  small-pox  and  up  to  the  date  of 
onset  of  symptoms  will  "  take "  and  pass 
through  its  typical  course. 

(g).  That  protection  is  afforded  against  small-pox  by 
vaccination  when  performed  within  three  days 
after  infection,  but  this  may  not  be  absolute  in 
cases  vaccinated  for  the  first  time ;  the  course 
of  the  disease,  however,  will  be  exceedingly 
mild. 

{h).  That  there  is  abundant  evidence  of  the  value  of 
vaccination  in  mitigating  the  severity  of  the 
disease  when  performed  at  any  time  after 
infection  up  to  date  of  onset,  and  even  after- 
wards. 

>-■ 


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